Low-density composite proppant, preparation method and applications thereof

The present invention provides a low-density composite proppant, which is prepared by carrying out a polymerization reaction on an oil phase and an aqueous phase, wherein the oil phase comprises, by weight, 60-90 parts of a monomer, 5-25 parts of a cross-linking agent, 0.01-10 parts of a filler, 0.1-5 parts of an initiator and 0-2 parts of a filler dispersant, and the aqueous phase comprises, by weight, 90-100 parts of water, 0.1-5 parts of a dispersant and 0.1-5 parts of an inorganic salt. The present invention further provides a preparation method of the proppant, wherein the preparation method comprises: uniformly mixing the dispersant, the inorganic salt and the water to obtain the aqueous phase, uniformly mixing the monomer, the cross-linking agent, the initiator, the filler and the optional filler dispersant to obtain the oil phase, mixing the oil phase and the aqueous phase, carrying out a polymerization reaction at a certain temperature to obtain a polymerization product system, and post-treating the obtained polymerization product system. The present invention further discloses applications of the proppant or the proppant prepared according to the method in reservoir fracturing reforming.